Dear Galaxy, I've been searching the lists for this type of issue and only found one solution thus far which is the use of a custom reference. It doesn't make sense in my situation because the reference I used was from Galaxy itself when I mapped my data. I'm now trying to use GATK to find SNPs but no matter what I've tried I can't get past this issue. I'm trying to use the Count Covariates and the Unified Genotyper but to no avail. The only issue appears to be that "Sequences are not currently available for the specified build." Any help would be much appreciated. Thanks Sincerely, Rich -- Richard Linchangco PSM in Bioinformatics College of Computing and Informatics University of North Carolina at Charlotte Tel: (630)440-7010 rlinchan@uncc.edu, rlinch2@gmail.com